Morphological Study of Myelinated Fibers of the Sciatic Nerve in Mice after Space Flight and Readaptation to the Conditions of Earth Gravity.

We revealed a decrease in the thickness of the myelin sheath and myelin delamination in the tibial nerve of C57BL/6N mice after a 30-day flight aboard the biosatellite Bion-M1. The processes of myelin degeneration continued for seven days after return of the animals to Earth and adaptation to the conditions of natural gravity. Our data add to hypothesis on the role of neurogenic component in pathogenesis of hypogravity motor syndrome.

Myelinated fibers of the mouse spinal cord after a 30-day space flight.

Myelinated fibers and myelin-forming cells in the spinal cord at the L3-L5 level were studied in C57BL/6N mice that had spent 30 days in space. Signs of destruction of myelin in different areas of white matter, reduction of the thickness of myelin sheath and axon diameter, decreased number of myelin-forming cells were detected in "flight" mice. The stay of mice in space during 30 days had a negative impact on the structure of myelinated fibers and caused reduced expression of the markers myelin-forming cells. These findings can complement the pathogenetic picture of the development of hypogravity motor syndrome.

[Effects of transplantation of human umbilical cord blood mononuclear cells, expressing VEGF and FGF2 genes, into the area of spinal cord traumatic lesion].

Effects of immediate single transplantation of human umbilical cord blood mononuclear cells (UCB-MC) transfected with recombinant vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF2) genes into the area of injury were studied on the model of rat spinal cord dosed contusion at TVIII level. UCB-MC transfected with EGFP-N2 plasmid were transplanted into the rats of the control group under similar conditions. The presence of EGFP- labeled cells were traced in white matter during 21 days after transplantation at a distance no less than 10 mm in rostral and caudal directions from the nearest point of the injection. By 30 days after the transplantation of UCB-MC transfected with pBud-VEGF-FGF2 plasmid, the cross-sectional area of sparing grey matter increased by more than 60% at a distance of 3 mm from the epicenter of injury. By that time, in the animals of this group, the number of perivascular cells expressing beta receptor of platelet-derived growth factor (PDGFbetaR) was increased by an average of 30% in the outer zones of white matter 1.5 cm from the injury epicenter. Delivery of the therapeutic genes VEGF and FGF2 to the damaged region and their expression in cell carriers stimulates vascularization and post-traumatic spinal cord regeneration.

[The adaptation of mycoplasmas to stress conditions: features of proteome shift in Mycoplasma hominis PG37 under starvation and low temperature].

Mycoplasma hominis--one of the widely spread mycoplasmas (class Mollicutes), associated with the socially significant human diseases and contamination of cell cultures. The solution of the problem on controlling M. hominis infections is connected with determination of the molecular basis, responsible for mechanisms of bacterium survival under unfavorable conditions. As a result of proteomic approach (2-DIGE and MALDI TOF/TOF MS) for the first time, 53 M. hominis PG37 proteins were detected, different abundance of which occurred at cultivating the bacterium under stress (starvation and low temperature) conditions. According to the classification of proteins by functional category (clusters of orthologous groups of proteins--COG), 47 of the 53 proteins of the mycoplasma are involved in the fundamental cellular and biochemical processes--translation (12; 22.64%), transcription (2; 3.77%), posttranslational modification (7; 13.20%), cell cycle control (2; 3.77%), energy production and conversion (6; 11.32%), carbohydrate transport and metabolism (3; 5.66%), amino acid transport and metabolism (8; 15.09%), nucleotide transport and metabolism (6; 11.32%), inorganic ion transport and metabolism (1; 1.89%). The functions of six proteins (11.32%) have not been found; 24 proteins (45.28%) are the factors of bacterium virulence. M. hominis PG37 proteins, the expression modulation of which arises under the unfavorable environmental conditions, are the components of adaptation mechanisms of the mycoplasma to the stressors and potential targets for controlling infections caused by this bacterium.

[Posttraumatic changes of rat spinal cord after transplantation of human umbilical cord blood mononuclear cells transfected with VEGF and FGF2 genes].

Using the model of the rat spinal cord dosed contusion injury at T8 level, cross sectional area of the pathological cavities was measured and the number of myelinated nerve fibers was calculated in the outer zones of white matter after immediate single injection in the damaged area of human umbilical cord blood mononuclear cells (UCB-MC) transfected with plasmid with vegf and fgf2 genes. UCB-MC transfected with pEGFP-N2 plasmid with egfp gene of enhanced green fluorescent protein were injected into the rats of control group under similar conditions. By Day 30 after the injection of UCB-MC transfected with vegf and fgf2 genes, total cross-sectional area of the cavities in outer zones of white matter at a distance of 3 mm caudally from the epicenter of the injury was reduced more than twice as compared with that found in control group. Number of myelinated nerve fibers in the same zones of white matter at the same distance from the epicentre in rostral and caudal directions, was increased by 20% on the average as compared with control, and at a distance of 5 mm in rostral direction--by 40 to 70%. Thus, the delivery to the injury region of the therapeutic genes vegf and fgf2 reduced cavitation, restrained the processes of secondary degeneration and supported the number of myelinated fibers in the injured spinal cord.

[About possible specialization of different compartments of a motoneuron axon for synthesis of specific proteins].

The spontaneous quantum secretion of neurotransmitter and its regulation through the system of presynaptic acetylcholine receptors have been studied on a neuromuscular preparation of rat m. soleus of intact animals and animals in which the axonal transport was blocked via the application of colchicine to the sciatic nerve. It was shown that, after six days of colchicine application, the spontaneous quantum secretion, the reaction of presynaptic membrane, and the reaction of neurosecretory apparatus to the depolarization of nerve endings via increase of the content of potassium ions in the environment and to the activation of presynaptic receptors by carbachol are not disturbed. Keeping in mind a rather short half-life of proteins that take part in the exocytosis and its regulation, it may be concluded that their functioning does not depend on the state of the axonal transport. These data correspond to the hypothesis put forward earlier that the synthesis of some proteins performing their function in nerve terminals occurs directly at the site of their utilization but not in the perikaryon, as it has been traditionally assumed.

Study of the efficiency of transplantation of human neural stem cells to rats with spinal trauma: the use of functional load tests and BBB test.

Human ensheating neural stem cells of the olfactory epithelium were transplanted to adult male rats immediately after contusion trauma of the spinal cord at T9 level rostrally and caudally to the injury. Voluntary movements (by a 21-point BBB scale), rota-rod performance, and walking along a narrowing beam were monitored weekly over 60 days. In rats receiving cell transplantation, the mean BBB score significantly increased by 11% by the end of the experiment. The mean parameters of load tests also regularly surpassed the corresponding parameters in controls. The efficiency of transplantation (percent of animals with motor function recovery parameters surpassing the corresponding mean values in the control groups) was 62% by the state of voluntary motions, 37% by the rota-rod test, and 32% by the narrowing beam test. Morphometry revealed considerable shrinking of the zone of traumatic damage in the spinal cord and activation of posttraumatic remyelination in animals receiving transplantation of human neural stem cells.